Touch panels may include optical systems, ultrasonic systems, capacitance systems, resistive systems and the like, depending on the method for detecting locations. From among these, resistive systems have a simple structure, and thus, are excellent in cost efficiency, and have been spreading rapidly in recent years. Resistive system touch panels are used for display panels of, for example, automated teller machines (ATM's) in banks and ticket dispensing machines in transportation facilities.
In the touch panel of such resistive systems, a transparent conductive multilayer body and glass with a transparent conductive thin film are placed so as to face each other with a spacer in between, providing a structure where a current flows through the transparent conductive multilayer body, so that the voltage in the glass with a transparent conductive thin film can be measured. When the transparent conductive multilayer body is made to make contact with the glass with a transparent conductive thin film through pressing operation with a finger, a pen or the like, a current passes through this contact portion, and thereby, the location of this contact portion is detected.
In recent years, the market for touch panels mounted in smart phones, PDA's (personal digital assistants), games and the like has been expanding, and reduction in the size of the frame of touch panels has been progressing. As a result, further increase in the durability against input by pen has become required in the vicinity of the peripheral portions of the touch panels.
A touch panel having a transparent conductive film where an anchor layer formed of a resin containing at least microscopic particles of which the average particle diameter is 1 nm to 30 nm, as well as an average coarseness Ra of 4 nm to 20 nm along the center line, an SiOx layer and a transparent conductive layer are provided on at least one surface of a transparent base film, for example, is disclosed as a touch panel as that described above (see Japanese Unexamined Patent Publication No. 2002-117724). In this configuration, however, a problem arises, such that the electrical resistance value on the surface of the transparent conductive layer changes and reliability is lacking.
In addition, a touch panel having a transparent conductive film where a base, an anchor layer for securing a conductive layer and a conductive layer are sequentially layered, for example, is disclosed as a touch panel as that described above (see Japanese Unexamined Patent Publication No. 2003-320609). This Japanese Unexamined Patent Publication No. 2003-320609 also describes that the anchor layer may be a silica layer formed in accordance with a plasma CVD method. In the invention described in Japanese Unexamined Patent Publication No. 2003-320609, however, durability against input by pen in the peripheral portions of the touch panel is not taken into consideration, though it is described that a touch panel for input by pen is sufficiently durable against application of pressure in a large sliding movement, and thus, a problem arises, such that durability against input by pen in the peripheral portions is inferior.